Schedule 14 


DEPARTMENT OF THE INTERIOR 

FRANKLIN K. LANE, Secretary 

BUREAU OF MINES 

VAN. H. MANNING, Director 


PROCEDURE FOR ESTABLISHING A LIST 
OF PERMISSIBLE GAS MASKS 

FEES, CHARACTER OF TESTS, AND 
CONDITIONS UNDER WHICH GAS 
MASKS WILL BE TESTED 



)<T-2 4 ^ / ■2- 


WASHINGTON 

GOVERNMENT PRINTING OFFICE 
1919 


The Bureau of Mines, in carrying out one of the provisions of its organic act—to 
disseminate information concerning investigations made—prints a limited free 
edition of each of its publications. 

When this edition is exhausted, copies may be obtained at cost price only through 
the Superintendent of Documents, Government Printing Office, Washington, D. 0. 

The Superintendent of Documents is not an official of the Bureau of Mines. His is 
an entirely separate office and he should be addressed: 

Superintendent of Documents, 

Government Printing Office , 
Washington , D. C. 

The general law under which publications are distributed prohibits the giving of 
more than one copy of a publication to one person. The price of this publication 
is 5 cents. 


2 


First edition , August , 1919 . 


0 * ©f 
SEP 24 1919 







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TH 13 

'll 45 


PROCEDURE FOR ESTABLISHING A LIST OF PERMISSIBLE GAS MASKS; 
FEES, CHARACTER OF TESTS, AND CONDITIONS UNDER WHICH GAS 
MASKS WILL BE TESTED. 


PRELIMINARY STATEMENT. 

AUTHORIZATION. 

An act of Congress (37 Stat., 681) approved February 25, 1913, 
contains the following provision in regard to tests or investigations 
performed by the Bureau of Mines: 

That for tests or investigations authorized by the Secretary of the Interior under the 
provisions of this act, other than those performed for the Government of the United 
States, or State governments within the United States, a reasonable fee covering the 
necessary expenses shall be charged, according to a schedule prepared by the Director 
of the Bureau of Mines, and approved by the Secretary of the Interior, who shall pre¬ 
scribe rules and regulations under which such tests or investigations may be made. 
All moneys received from such sources shall be paid into the Treasury to the credit 
of miscellaneous receipts. 

The Bureau of Mines will make tests at its Pittsburgh experiment 
station to establish a list of permissible gas masks and respirators that 
are safe for use in air containing limited percentages of certain irre- 
spirable gases, vapors, or smokes. As regards their design and 
approval, gas-mask canisters, or absorbent containers, are subdivided 
into the following five classes or types: 

Type A: For acid gases, such as carbon dioxide, chlorine, formic 
acid, hydrogen chloride, hydrogen cyanide, hydrogen sulphide, 
nitrogen peroxide, phosgene, and sulphur dioxide. 

Type B: For organic vapors, such as acetone, alcohol, aniline, 
benzine, carbon bisulphide, carbon tetrachloride, chloroform, ether, 
formaldehyde, gasoline and petroleum distillates, toluene, and 
similar volatile compounds. 

Type C: For ammonia. 

Type D: For other special individual gases. 

Type E: For dusts, chemical smokes, fumes, and mists, such as tin 
tetrachloride, silicon tetrachloride, titanium tetrachloride, and 
sulphur trioxide. 

Type AB, AC, etc.: For combinations of the preceding types. 

120989°—19 3 


I 



4 


ESTABLISHING A LIST OF PERMISSIBLE GAS MASKS. 


DEFINITION OF PERMISSIBLE. 

The Bureau of Mines considers a gas mask permissible for use in 
air containing certain irrespirable gas or gases if all the details of 
construction and the chemical properties of the absorbent are the 
same in all respects as those of the gas masks that met the require¬ 
ments and passed the inspection and tests of the Bureau of Mines, as 
hereinafter described. 

CONDITIONS UNDER WHICH GAS MASKS WILL BE TESTED. 

The conditions under which the Bureau of Mines will examine and 
test gas masks to establish their permissibility against gases are as 
follows: 

1. The examination and tests will be made at the experiment sta¬ 
tion of the Bureau of Mines at Pittsburgh, Pa. 

2. Applications for tests shall be addressed to the Director, Bureau 
of Mines, Washington, D. C., and shall be accompanied by a complete 
description of the gas mask to be tested, a full set of drawings, showing 
all the details of construction, and statements that are explained 
in the next paragraph. 

The capacities of absorbents for gases vary over wide limits, depend¬ 
ing on the materials used and the conditions under which each lot 
or batch is manufactured. Hence it will be necessary that each lot 
obtained by a manufacturer be tested for capacity before being used 
in gas masks, in order to obtain the standard set by the Bureau of 
Mines. For these reasons the bureau requires a statement with each 
application to show the nature, the adequacy, and the continuity of 
such control provided by the applicant. Tests for approval will be 
made only after the bureau is satisfied of the effectiveness of such 
control, and approvals once granted will remain in force only while 
the control is sustained. 

3. A copy of the description, a duplicate set of drawings, a copy 
of the statements concerning the control of the quality of the absorb¬ 
ents, and two complete gas masks, identical in every way with 
those offered for sale, shall be sent, prepaid, to the Supervising 
Chemist, Bureau of Mines, 4,800 Forbes Street, Pittsburgh, Pa. In 
the event of the apparatus successfully passing all of the Bureau of 
Mines tests and requirements hereinafter specified, one set will be 
retained by the Bureau of Mines as a laboratory exhibit, and the 
other will be returned to the owner. In the event that an apparatus 
does not pass all of the bureau’s tests or requirements, both sets will 
be returned to the owner. 

4. Each gas mask shall have marked on it in a distinct manner 
the name of the manufacturer and the name, letter, or number by 
which the type is designated for trade purposes, and a written state¬ 
ment shall be made whether or not the apparatus is ready to be 


REQUIREMENTS FOR BUREAU OF MINES APPROVAL. 5 

marketed. No gas mask will be tested unless it is in the completed 
form in which it is to be put on the market. 

5. As soon as possible after the receipt of his application for test, 
the manufacturer will be notified of the date on which his gas mask 
will be tested, and the material that it will be necessary for him to 
submit. 

6. All material for test shall be delivered by the manufacturer to 
the Supervising Chemist, Bureau of Mines, 4800 Forbes Street, Pitts¬ 
burgh, Pa., not less than one week prior to the date set for the test. 

7. No one is to be present at these tests except the necessary 
Government officials, their assistants, and one representative of the 
manufacturer of the gas mask to be tested, who shall be present in 
the capacity of an observer only. 

8. The conduct of the tests shall be entirely in the hands of the 
bureau’s representatives in charge of the investigation. 

9. The tests will be made in the order that the applications for 
test are received, provided the necessary material is submitted at 
the proper time. 

10. The details of the results of tests shall be regarded as confi¬ 
dential by all present at the tests, and shall not be made public in 
any way prior to their official publication by the Bureau of Mines. 

11. The results of tests of the gas masks that fail to pass the 
requirements shall not be made public, but shall be kept confidential, 
except that the person submitting the apparatus will be informed 
with a view to possible remedy of the defects in future gas masks 
submitted, but such changes will not be permitted while testing is 
in progress. 

12. Tests will be made for manufacturers or accredited manufac¬ 
turers’ agents and for inventors. 

13. A list of permissible gas masks and respirators and the results 
of their tests will be made public from time to time by the Bureau 
of Mines. 

REQUIREMENTS FOR BUREAU OF MINES APPROVAL. 

To obtain the approval of the Bureau of Mines, a gas mask or 
respirator must pass successfully the inspection and tests described 
below: 

1. Color and markings .—Distinctive color and markings to indicate 
the purpose of each canister or absorbent container are required for 
the purpose of safeguarding the wearers. The colors required are 
indicated in the table following. 


6 


ESTABLISHING A LIST OF PERMISSIBLE GAS MASKS. 


Table of colors to indicate purpose of masks. 


Mask type-letter. 


Chemical properties of 
gases absorbed. 


Acid. 


B. 

C. 

D. 

E. 

AB . 

Combinations of those 
above. 


Organic vapor. 

Ammonia. 

Other special individual 
gases. 

Dusts, smokes, mists. 

Acid and organic vapors. . 

Combinations of those 
above. 


v 

Distinctive color required. 


White. 

Black. 

Green. 

Color to be assigned. 


White or black stripes. 

Yellow. 

Combinations of those 
above. When a dust 
filter is combined with 
a gas respirator, it is to 
be indicated by black 
or white stripes. 


The canisters, or containers, for the absorbent material shall be 
either painted completely in these colors or the color shall be made 
a distinctive part of the canister design. On the canister shall be 
indicated, in bold letters, this statement: 

For Use Only in.... 

(Name of gas or gases.) 

The manufacturer will state the gas or gases, or classes of gases, 
in which the gas mask is to be used. For this purpose, it is permis¬ 
sible to attach a metal plate bearing the proper inscription in raised 
or other distinct letters, or to stamp the statement into the metal of 
the can with a male and female die. The statement may be printed 
or stenciled with paint, or paper labels may be used. The latter 
must be attached with a heat-proof cement and varnished to prevent 
loosening by moisture. This statement may be made a part of the 
approval plate described on page 11. 

If a dust respirator is combined with gas absorbents, the fact 
should be indicated, as for example: 

For Use Only in __and in Dusts. 

(Name of gas or gases.) 

The knapsack or case in which the gas mask is kept must also 
have the same statement indicated conspicuously in bold letters. 
The distinctive color or colors may be that of the letters themselves 
or that of the background, or part of the design, in such fashion that 
the distinctive colors are prominent. 























Requirements for bureau of mines approval. 


7 


Metal plates or painted or printed stencils may be used on the 
knapsacks, but paper labels will not be permissible here. 

For chemical smokes or fumes, the canister or container for the 
absorbent material shall be of a color to indicate the purpose of the 
absorbent material contained, and shall be striped with a strongly 
contrasting color, either black or white, to indicate the filters. The 
stripes may be placed so as to indicate the number and position of 
the filters. On the canister or container shall be indicated, in bold 
letters of contrasting color, this statement. 

For Use Only in __ 

(Name of gas or gases and of chemical fume, according to the purpose of the manufacturer.) 

The knapsack or case in which the gas mask is kept must also 
have the same statement indicated, in bold letters on a striped back¬ 
ground of the proper colors, to indicate the purpose of the absorbent 
and the filter. 

2. Materials .—The gas mask and equipment must be constructed 
in all its parts of materials suitable for the purpose they must serve. 
This applies to the fabric, rubber, metal, chemical, and other parts. 

3. Design and construction .—The excellence of design and mechan¬ 
ical construction, as well ais the workmanship, will be considered. 
This will be done with regard to safety to the wearer, freedom of his 
movements and his vision, the fit of the face and head pieces and the 
comfort that is afforded under all conditions of use. There will also 
be considered the ease with which canisters or other parts of neces¬ 
sarily short life may be replaced by fresh parts, and the tightness of the 
whole apparatus, with a view to insuring the wearer against leaks of 
unpurified air, both before and after such changes are made. 

4. Face-piece test .-—Two men wearing the gas masks will enter a 
room containing 1 per cent of sulphur dioxide; if necessary, a canis¬ 
ter for acid gases will be attached to the mask for this test. Thirty 
minutes will be spent in work designed to provide observations on the 
freedom of movement permitted, freedom from leaks, and the 
comfort allowed to the wearer. The time will be divided as follows: 

10 minutes. Walking, turning head, dipping chin. 

5 minutes. Calisthenic movements, such as swinging arms, 
turning body, bending body at hips. 

10 minutes. Sitting at rest, then walking and easy movements. 

5 minutes. Pumping air into gas cylinder of about 1 cubic foot 
capacity, with a tire pump, to a pressure of 25 
pounds. 

To meet approval, it will be necessary that no sulphur dioxide come 
through the mask during the test, and that no undue discomfort be 
experienced because of the fit or other mechanical features of the gas 
mask. 






8 


ESTABLISHING A LIST OF PERMISSIBLE GAS MASKS. 


5. Resistance to flow of air .— 

(a) Before and after the chemical tests described under paragraphs 
6 and 7, the pressure drop of air passing through the canisters at a 
rate of 85 liters per minute will be determined in inches of water- 
column height. At no time must the resistance exceed 4 inches of 
water. 

(b) The resistance to flow of air of the complete mask and canister, 
to inspiration and to expiration, will be determined on a mechanical 
apparatus, the rate being 85 liters per minute continuous flow; the 
resistance must not exceed 6 inches of water pressure. 

6. Canister tests .— 

Type A, acid gases: Nine canisters or parts containing the absorb¬ 
ent, separated from the face pieces and harness, will be tested on a 
chemical testing apparatus under these conditions: 

(а) Number of canisters. Three. 

Gas used for testing. Chlorine. 

Concentration of chlorine in air. 5,000 parts per million. 

Humidity. 50 per cent relative humidity. 

Temperature. Room temperature (approximately 25° C.). 

Rate of flow of gas. 32 liters per minute, continuous flow. 

(б) Number of canisters. Three. 

Gas used for testing. Hydrogen cyanide. 

Concentration of hydrogen cyanide in air. 5,000 parts per 
million. 

Humidity. 50 per cent relative humidity. 

Temperature. Room temperature (approximately 25° C.) 

Rate of flow of gas. 32 liters per minute, continuous flow. 

(c) Number of canisters. Three. 

Gas used in testing. Sulphur dioxide. 

Concentration of sulphur dioxide in air. 5,000 parts per 
million. 

Humidity. 50 per cent relative humidity. 

Temperature. Room temperature (approximately 25° C.). 

Rate of flow of gas. 32 liters per minute, continuous flow. 

Tested in this way, the life or service time of each canister must 
be at least 20 minutes. The end of the life will be the time at which 
a test shows 5 parts per million of chlorine, hydrogen cyanide, or sul¬ 
phur dioxide in the air coming from the canisters. 

Type B, organic vapors: Three canisters or parts containing 
absorbent, separated from the face pieces and harness, will be tested 
on a chemical apparatus under the following conditions: 

Vapor used for testing. Carbon tetrachloride. 

Concentration of carbon tetrachloride in air. 5,000 parts per 
million. 

Humidity. 50 per cent relative humidity, 


REQUIREMENTS FOR BUREAU OF MINES APPROVAL. 9 

Temperature. Room temperature (approximately 25° C.). 

Rate of flow of gas. 32 liters per minute, continuous flow. 

Tested in this way, the life or service time of each canister must he 
at least 20 minutes. The end of the life will be the time at which 
the air, after passing through the canister, imparts a green color 
to a small gas flame containing some of the air admixed with the 
gas and impinging on a clean copper wire. 

Type C, ammonia: Three canisters containing the absorbent, 
separated from, the face pieces and harness, will be tested on a chemi¬ 
cal testing apparatus, under the following conditions: 

Concentration of ammonia in air. 20,000 parts per million, or 2 
per cent by volume. 

Humidity. 50 per cent relative humidity. 

Temperature. Room temperature (approximately 25° C.). 

Rate of flow of gas. 32 liters per minute, continuous flow. 

Tested in this way, the life or service time must he at least 20 
minutes. The end of the life will be the time at which the air, after 
passing through the canister, contains 100 parts per million, or 0.01 
per cent by volume, of ammonia. 

Type D, other special individual gases: Similar tests will be per¬ 
formed on other special gases, and will be arranged as the need 
arises. 

Type E, smoke, dust, and mist filters: Three filters, separated from 
the face piece and harness, will be tested on a smoke-testing apparatus 
under these conditions: 

Fume used. Tobacco smoke. 

Rate of flow of gas. 85 liters per minute. 

Length of test. 5 minutes. 

Tested in this way, the filter must retain at least 95 per cent of 
the passing tobacco smoke at the end of the 5-minute period. 

Other types: Combinations for different types of gases, as above. 
Canisters may be tested according to two or more methods, under 
Types A, B, C, D, and E, to secure approval for different gases 
classed under the different types. 

To meet the approval of the Bureau of Mines, it will be necessary 
that the life for gases in each class or type be equal to the separate 
requirements. 

7. Chemical stability .—To determine the chemical stability under 
extreme conditions of dryness and moisture, two canisters will be 
subjected to each of the following tests for which approval is desired: 

(a) Air free of carbon dioxide, at room temperature and 25 per 
cent relative humidity, will be passed through each canister, at a 
rate of 64 liters per minute, for a period totaling 6 hours. The 


10 


ESTABLISHING A LIST OP PERMISSIBLE GAS MASKS. 


canisters will then be tested, as described under paragraph 4 ; against 
gases, as follows: 

Approval for acid gas. Chlorine. 

Approval for organic vapor. Carbon tetrachloride. 

Approval for ammonia. Ammonia. 

Approval for special gas. Special gas to be arranged. 

Approval for dusts and mists. No test. 

Approval for combinations. Any two or more of the above. 

To meet approval, the life of the canisters must not fall below 10 
minutes in any test. 

( b ) Air free of carbon dioxide, at room temperature and 85 per 
cent relative humidity, will be passed through each of two canisters 
at a rate of 64 liters per minute, for a period totaling 6 hours, and 
the canisters will then be tested as described in (a) above. 

To meet approval, the life of the canisters must not fall below 10 
minutes in any test. 

8. High rates of breathing and maximum concentration .—To insure 
protection to the wearer at high rates of breathing in gas of high 
concentration, a stream of air containing 1 per cent of gas and flowing 
at a rate of 64 liters per minute will be passed continuously through 
a canister. The other conditions of the tests will be these: 

Humidity. 50 per cent relative humidity. 

Temperature. Room temperature (approximately 25° C.). 

Gas used in testing— 

Approval for acid gas. Phosgene. 

Approval for organic vapors. Carbon tetrachloride. 

Approval for special gas. Ammonia, or other special gas. 

Approval for dusts and mists. No test. 

Approval for combinations. Any two or more of the above. 

Concentration. 10,000 parts per million, or 1 per cent by volume, 
for any gas. 

Number of canisters. Two, tested against any gas. 

To meet the approval of the Bureau of Mines, the life of the canis¬ 
ters under any of the above tests against gas must be at least five 
minutes. 

APPROVAL FOR HIGHER CONCENTRATIONS. 

The Bureau of Mines requires that a gas mask pass the tests out¬ 
lined in the preceding paragraphs in order to obtain approval for use 
in concentrations of 1 per cent of gas, which is the minimum for 
which the bureau will grant approvals. To obtain approval for 
higher concentrations, the canister must pass tests similar in every 
way to those that have been described, except that the concentration 
is increased in test 8 in steps of 1 per cent, as far as practicable, and 
these tests are made on each gas for which approval in higher con- 


WITHDRAWAL OF APPROVAL. 


11 


centrations than 1 per cent is desired. Approval will be granted for 
use ol the gas masks in the maximum concentration for which they 
successfully pass the test. 

CHANGING OF DETAILS OF TESTS. 

If the mechanical or other features of a gas mask render it advisable 
to omit any of the tests or part of a test previously described, or 
to perform accessory tests, the bureau reserves the right to modify 
the test in such manner as to obtain substantially the same informa¬ 
tion and degree of safety as is provided by the tests described. 

APPROVAL OF PERMISSIBLE GAS MASKS. 

The manufacturer will be required to attach to the canisters used 
with the respirators a plate bearing the seal of the Bureau of Mines 
and inscribed as follows: 

Permissible Gas Mask (or Respirator) For . In Concentrations 

not Exceeding.Per Cent. 

U. S. Bureau op Mines Approval No. 

The manufacturer will insert in the blanks the name or names of 
any or all gases for which the gas mask was approved. The plate 
may be fashioned in any way, as described on page 6. 

NOTIFICATION OF MANUFACTURER. 

As soon as the bureau’s chemists are satisfied that a gas mask is 
permissible, the manufacturers of the mask and the public-safety 
departments of the several States shall be notified to that effect. As 
soon as a manufacturer receives formal notification that his gas 
mask has passed the tests prescribed by the bureau, he shall be free 
to advertise such a gas mask as permissible. 

SCOPE OF APPROVAL. 

The bureau’s approval of any gas mask shall be construed as 
applying to all gas masks made by the same manufacturer that have 
the same construction in all details and have equal chemical quali¬ 
ties in the absorbent, as considered by the bureau. 

As stated on page 4, chemical control of the quality of the ab¬ 
sorbent must be sustained by the manufacturer during the time 
that the approval is operative. 

WITHDRAWAL OF APPROVAL. 

The Bureau of Mines reserves the right to rescind for cause at any 
time any approval granted under the conditions as herein set forth. 
At times gas masks or parts may be purchased on the open market 
by the Bureau of Mines and tested. Failure to meet the requirements 
for approval will be cause for withdrawing the approval granted. 





12 


ESTABLISHING A LIST OF PERMISSIBLE GAS MASKS. 


FEES FOR TESTING GAS MASKS. 

The following schedule of fees to cover expenses to be charged on 
and after May 22, 1919, has been established and approved by the 
Secretary of the Interior, in accordance with the provisions of the 
statute previously quoted: 

Table of costs for approval. 


Types of gas mask. 

Examination 
and test of 
complete 
mask with 
canister. 

Examination 
and test of 
canister only. 

• 

Additional 
tests and ex¬ 
amination of 
canister in 
connection 
with other 
tests. 

A. 

$200.00 

$170.00 

$150.00 

B. 

140.00 

105. 00 

85.00 

C. 

150.00 

110.00 

40.00 

D. 

225.00 

190.00 

155. 00 

E. 

100.00 

65.00 

50.00 

AB. 

285.00 

255.00 

235.00 


The costs stated above are for maximum concentrations of 1 per 
cent. Tests for approval of gas masks at concentrations higher than 
1 per cent will cost $40 in addition to the costs given in the preceding 
table, for each gas investigated. 

The fees specified herein may be increased to cover the cost of 
testing an unusually complicated apparatus, or performing unusually 
difficult tests, and are also subject to change upon the recommenda¬ 
tion of the Director of the Bureau of Mines and the approval of the 
Secretarv of the Interior. 


REMITTANCES. 

Manufacturers who submit gas masks for tests to determine their 
permissibility will be required to furnish certified check or bank 
draft, made payable to the Secretary of the Interior, to cover the 
fee for the tests. Such fee must be received at least two weeks 
prior to the date set for beginning the tests; otherwise, the equip¬ 
ment of the next applicant upon the list will be tested. 

SYNOPSIS OF PROCEDURE TO BE FOLLOWED IN MAKING APPLICA¬ 
TIONS FOR TESTS, SUBMITTING MATERIAL, CONDUCTING TESTS, 
AND NOTIFYING APPLICANT OF RESULTS. 

1. Application for tests should be addressed to the Director of the 
Bureau of Mines, Washington, D. C. This application should be 
accompanied by check or draft, a complete description of the respi¬ 
rator to be tested, a statement to show the nature, adequacy and 

















SYNOPSIS OF PROCEDURE TO BE FOLLOWED. 


13 


continuity of the chemical control of the absorbent material which is 
to be maintained by the applicant, and a set of drawings described in 
paragraph 2, page 4. Duplicate copies of the application, descrip¬ 
tion, statements, and drawings should be sent to the Supervising 
Chemist, Bureau of Mines, 4800 Forbes Street, Pittsburgh, Pa., 
accompanied by two complete gas masks. 

2. As soon as the application has been received by the bureau’s 
chemists, the applicant will be notified of the date of the tests and 
the number of gas masks it will be necessary for him to submit. 

3. After receiving this notification, the applicant should send the 
material required to the Supervising Chemist, Bureau of Mines, 
4800 Forbes Street, Pittsburgh, Pa. The material should be delivered 
not less than one week in advance of the date set for the beginning of 
the tests. At this time, the applicant should state the name and 
address of the applicant's representative who will witness the tests. 

4. The tests will be begun on the date set and continued until the 
gas mask is approved, rejected, or withdrawn. 

5. After the bureau’s chemists have considered the results of the 
tests, a formal report of the approval or disapproval of the respirator 
will be made to the applicant in writing by the Director of the 
Bureau of Mines. No verbal report will be made, and the details of 
the tests must be regarded as confidential by all present. 

(Signed) Van. H. Manning, 

Director. 

Approved: May 22, 1919. 

John W. Hallowell, 

Assistant to the' Secretary. 

o 









